Is their any Query format which can change the value based on conditional
expression is TRUE!!!
Thanks..
Techi -
On Fri, Aug 2, 2013 at 2:11 PM, Hick Gunter <h...@scigames.at> wrote:
> The SQL you gave translates to
>
> "Change the 'Name' field to have the value 'test' in all records where the
> 'ID' field has the value 2".
>
> If there is no such record, then SQL has nothing to do and very
> successfully does exactly nothing.
>
> SQL is "set oriented" and update operations on empty sets always succeed.
>
> I guess you are thinking along procedural/file oriented lines as in
> pseudocode
>
> record.id = 2;
> error = readwithlock( file, byID, &record );
> if (error) raise exception;
> record.name = 'test';
> error = updatewithunlock ( file, &record );
> if (error) raise exception;
>
> SQLite implements UPDATE as a SELECT followed by REPLACE statemenst as if
> written like
>
> (INSERT OR) REPLACE INTO table SELECT id,'test' FROM table WHERE id =
> 2;
>
> Which is equivalent to (naïve, not using index) pseudocode like
>
> open( file );
> while (! eof( file ) )
> {
> error = readseqwithlock( file, &record );
> if (error) raise exception;
> if (record.id == 2)
> {
> record.name = 'test';
> error = updatewithunlock( file, &record );
> if (error) raise exception;
> } else {
> error = unlock( file );
> if (error) raise exception;
> }
> }
>
> HTH
> Gunter
>
> -----Ursprüngliche Nachricht-----
> Von: techi eth [mailto:techi...@gmail.com]
> Gesendet: Freitag, 02. August 2013 10:15
> An: General Discussion of SQLite Database
> Betreff: [sqlite] Where Clause
>
> Come across one issue with conditional query execution.
>
> Query: UPDATE COMPANY SET Name= 'test' WHERE ID = 2; According to my
> understanding if no ID = 2 is present in table then error should return but
> it return with SQLITE_OK however Name value is not changed.
>
> Cheers -
> Techi
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>
> --------------------------------------------------------------------------
> Gunter Hick
> Software Engineer
> Scientific Games International GmbH
> Klitschgasse 2 – 4, A - 1130 Vienna, Austria
> FN 157284 a, HG Wien
> Tel: +43 1 80100 0
> E-Mail: h...@scigames.at
>
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